The present invention relates to aerogel particles, products containing the same, processes of making the same, and uses thereof.
Aerogel particles can have a very low density, high porosity, and small pore diameters. They can be extremely light weight and are usually formed by replacing the particles in a gel with a gas. Aerogel particles have a wide range of uses. For example, aerogels, in particular those with porosities of greater than about 60% and densities of less than about 0.4 g/cc, can exhibit very low thermal conductivity. Therefore, aerogels are used as thermal insulating materials as described, for example, in EP-A-0 171 722, incorporated in its entirety by reference herein. A class of aerogels includes silica gel particles. Silica gel materials are used in a wide variety of applications including matting agents, catalysts, personal care products, and chromatography to name a few.
Commercially produced silica gel materials can typically have large surface areas and void volumes and have narrow pore size distributions in the mesopore and micropore ranges. The lower limit of the particle size distribution of these materials is typically more than 3 microns which can be achieved by air jet milling of the dried silica gel powder. Thus, current processes do not permit the production of smaller particles, thereby limiting the use of silica gels or aerogels.
There is also a need to provide a tighter particle distribution range that can lead to better quality control of the finished product since each batch of material preferably has more similar physical properties.
Accordingly, there is a need for particles that avoid one or more of the above-described disadvantages.